On 12/05/2012 07:57 AM, Haispkt Chau Quang wrote:
Dear ,
I start finding about player/stage, i'm new about it. pls advise if any.
I'm doing the map building using laser 2D. i have something i do not clear about it. 
May you help me?
  1. do you have any method to build the map. pls advise me.
  2.  i'm trying to understand how lazer sensor work, i simulated laserobstacleavoid.cc , i showed some data from program but i'm not clear about these number: 
                    - Number lp[R]= -1610612736: is that the distance from robot to obstacle? is it meter or what? why we have negative number?
Now i'm doing: Map building for robot. thanks you very much.
i can not attached the picture.it showed that it is over 40kb

Quang Hai

What is lp[R]?  Without seeing the code, knowing what versions of Player and Stage you're using, and seeing the config files you're running, it's nearly impossible to know what you're talking about.  Please see the Getting Help[1] page on the wiki.

1. To build a map, you can either use a driver lib the "mricp" which builds a map, or you can implement your own mapping code.  There currently aren't a lot of mapping algorithms built into Player; I'd be glad to add any implementations that were contributed.
2. "lp" is a variable in laserobstacleavoid.cc, but it's a LaserProxy class.  The [] operator is overloaded to print out a range value, but it will be uninitalized until robot.Read() is called enough that lp.IsValid() returns true, and it should only be in the range of [0, ranges_count - 1]


[1] http://playerstage.sourceforge.net/wiki/Getting_help